The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus in which a photosensitive recording medium is exposed to light by a planar illuminator serving as a light source.
Heretofore, there is known an image recording apparatus for recording an image according to electrophotograhpic process. A recording medium used in such an apparatus is uniformly pre-charged to one of the polarities. There is also known an image recording apparatus using a photosensitive pressure-sensitive recording medium proposed in U.S. Pat. No. 4,399,209 to Sanders et al. On one surface of the recording medium, microcapsules encapsulating chromogenic material and photocuring resin are uniformly coated, and when the recording medium is exposed to light, the microcapsules are selectively photocured, whereas the rest of the microcapsules remain uncured. The recording medium thus exposed to light is brought in facial contact with a developer sheet and both are pressed against each other. Upon applying pressure to the recording medium, the uncured microcapsules are ruptured and the chromogenic material flown out of the microcapsules react with a developer material coated on the developer sheet, so that a visible image is formed on the developer sheet.
In the two recording apparatuses described above, a CRT (cathode ray tube) can be used as a light source. The CRT is disposed so that its ilumination surface confronts the photosensitive recording medium, between which an optical system such as a spherical lens or an optical fiber bundle is disposed to apply light from the CRT illumination surface onto the surface of the photosensitive recording medium.
In the exposure by the CRT, a variety of photo-sensitive recording media can be exposed to light emitted from a fluorescent substance if the latter is selected so that the wavelength of the light falls within a specified range of sensitivity Of the individual photo-sensitive recording medium. Further, selection of the fluorescent substance enables to compensate for the sensitivity characteristics of the individual photosensitive recording medium.
However, in the case where a CRT is used as a light source, partly because a CRT is usually as deep as its screen and hence is heavy in weight, and partly because an electron gun and a grid are required to be impressed with a high voltage of several kilovolts, the entire apparatus would inevitably be large in size and heavy in weight. Further, with CRTs now on the market, it is difficult to expect an improved resolution power of a picture image.